Commit 846d6da1 authored by Maxim Mikityanskiy's avatar Maxim Mikityanskiy Committed by Saeed Mahameed

net/mlx5e: Fix division by 0 in mlx5e_select_queue

mlx5e_select_queue compares num_tc_x_num_ch to real_num_tx_queues to
determine if HTB and/or PTP offloads are active. If they are, it
calculates netdev_pick_tx() % num_tc_x_num_ch to prevent it from
selecting HTB and PTP queues for regular traffic. However, before the
channels are first activated, num_tc_x_num_ch is zero. If
ndo_select_queue gets called at this point, the HTB/PTP check will pass,
and mlx5e_select_queue will attempt to take a modulo by num_tc_x_num_ch,
which equals to zero.

This commit fixes the bug by assigning num_tc_x_num_ch to a non-zero
value before registering the netdev.

Fixes: 214baf22 ("net/mlx5e: Support HTB offload")
Reported-by: default avatarJesper Dangaard Brouer <brouer@redhat.com>
Signed-off-by: default avatarMaxim Mikityanskiy <maximmi@mellanox.com>
Reviewed-by: default avatarTariq Toukan <tariqt@nvidia.com>
Signed-off-by: default avatarSaeed Mahameed <saeedm@nvidia.com>
parent 4eacfe72
...@@ -4979,6 +4979,11 @@ void mlx5e_build_nic_params(struct mlx5e_priv *priv, struct mlx5e_xsk *xsk, u16 ...@@ -4979,6 +4979,11 @@ void mlx5e_build_nic_params(struct mlx5e_priv *priv, struct mlx5e_xsk *xsk, u16
priv->max_nch); priv->max_nch);
params->num_tc = 1; params->num_tc = 1;
/* Set an initial non-zero value, so that mlx5e_select_queue won't
* divide by zero if called before first activating channels.
*/
priv->num_tc_x_num_ch = params->num_channels * params->num_tc;
/* SQ */ /* SQ */
params->log_sq_size = is_kdump_kernel() ? params->log_sq_size = is_kdump_kernel() ?
MLX5E_PARAMS_MINIMUM_LOG_SQ_SIZE : MLX5E_PARAMS_MINIMUM_LOG_SQ_SIZE :
......
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